clk-main.c
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/*
* Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
*/
#include <linux/clk-provider.h>
#include <linux/clkdev.h>
#include <linux/clk/at91_pmc.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include "pmc.h"
#define SLOW_CLOCK_FREQ 32768
#define MAINF_DIV 16
#define MAINFRDY_TIMEOUT (((MAINF_DIV + 1) * USEC_PER_SEC) / \
SLOW_CLOCK_FREQ)
#define MAINF_LOOP_MIN_WAIT (USEC_PER_SEC / SLOW_CLOCK_FREQ)
#define MAINF_LOOP_MAX_WAIT MAINFRDY_TIMEOUT
struct clk_main {
struct clk_hw hw;
struct at91_pmc *pmc;
unsigned long rate;
unsigned int irq;
wait_queue_head_t wait;
};
#define to_clk_main(hw) container_of(hw, struct clk_main, hw)
static irqreturn_t clk_main_irq_handler(int irq, void *dev_id)
{
struct clk_main *clkmain = (struct clk_main *)dev_id;
wake_up(&clkmain->wait);
disable_irq_nosync(clkmain->irq);
return IRQ_HANDLED;
}
static int clk_main_prepare(struct clk_hw *hw)
{
struct clk_main *clkmain = to_clk_main(hw);
struct at91_pmc *pmc = clkmain->pmc;
unsigned long halt_time, timeout;
u32 tmp;
while (!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCS)) {
enable_irq(clkmain->irq);
wait_event(clkmain->wait,
pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCS);
}
if (clkmain->rate)
return 0;
timeout = jiffies + usecs_to_jiffies(MAINFRDY_TIMEOUT);
do {
halt_time = jiffies;
tmp = pmc_read(pmc, AT91_CKGR_MCFR);
if (tmp & AT91_PMC_MAINRDY)
return 0;
usleep_range(MAINF_LOOP_MIN_WAIT, MAINF_LOOP_MAX_WAIT);
} while (time_before(halt_time, timeout));
return 0;
}
static int clk_main_is_prepared(struct clk_hw *hw)
{
struct clk_main *clkmain = to_clk_main(hw);
return !!(pmc_read(clkmain->pmc, AT91_PMC_SR) & AT91_PMC_MOSCS);
}
static unsigned long clk_main_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
u32 tmp;
struct clk_main *clkmain = to_clk_main(hw);
struct at91_pmc *pmc = clkmain->pmc;
if (clkmain->rate)
return clkmain->rate;
tmp = pmc_read(pmc, AT91_CKGR_MCFR) & AT91_PMC_MAINF;
clkmain->rate = (tmp * parent_rate) / MAINF_DIV;
return clkmain->rate;
}
static const struct clk_ops main_ops = {
.prepare = clk_main_prepare,
.is_prepared = clk_main_is_prepared,
.recalc_rate = clk_main_recalc_rate,
};
static struct clk * __init
at91_clk_register_main(struct at91_pmc *pmc,
unsigned int irq,
const char *name,
const char *parent_name,
unsigned long rate)
{
int ret;
struct clk_main *clkmain;
struct clk *clk = NULL;
struct clk_init_data init;
if (!pmc || !irq || !name)
return ERR_PTR(-EINVAL);
if (!rate && !parent_name)
return ERR_PTR(-EINVAL);
clkmain = kzalloc(sizeof(*clkmain), GFP_KERNEL);
if (!clkmain)
return ERR_PTR(-ENOMEM);
init.name = name;
init.ops = &main_ops;
init.parent_names = parent_name ? &parent_name : NULL;
init.num_parents = parent_name ? 1 : 0;
init.flags = parent_name ? 0 : CLK_IS_ROOT;
clkmain->hw.init = &init;
clkmain->rate = rate;
clkmain->pmc = pmc;
clkmain->irq = irq;
init_waitqueue_head(&clkmain->wait);
irq_set_status_flags(clkmain->irq, IRQ_NOAUTOEN);
ret = request_irq(clkmain->irq, clk_main_irq_handler,
IRQF_TRIGGER_HIGH, "clk-main", clkmain);
if (ret)
return ERR_PTR(ret);
clk = clk_register(NULL, &clkmain->hw);
if (IS_ERR(clk)) {
free_irq(clkmain->irq, clkmain);
kfree(clkmain);
}
return clk;
}
static void __init
of_at91_clk_main_setup(struct device_node *np, struct at91_pmc *pmc)
{
struct clk *clk;
unsigned int irq;
const char *parent_name;
const char *name = np->name;
u32 rate = 0;
parent_name = of_clk_get_parent_name(np, 0);
of_property_read_string(np, "clock-output-names", &name);
of_property_read_u32(np, "clock-frequency", &rate);
irq = irq_of_parse_and_map(np, 0);
if (!irq)
return;
clk = at91_clk_register_main(pmc, irq, name, parent_name, rate);
if (IS_ERR(clk))
return;
of_clk_add_provider(np, of_clk_src_simple_get, clk);
}
void __init of_at91rm9200_clk_main_setup(struct device_node *np,
struct at91_pmc *pmc)
{
of_at91_clk_main_setup(np, pmc);
}